Electronic (Computerized) Crossmatch

Some labs have moved to an electronic (computer-assisted) crossmatch in which donor blood is issued based on the blood bank information system (computer) ensuring that the patient and donor are ABO-compatible. Widespread use of this protocol became possible when the AABB Standards sanctioned its use in 1993 (Standards for Blood Banks and Transfusion Services, 15th ed. Bethesda, MD: American Association of Blood Banks, 1993). It is common for countries such as Canada and others to use the AABB Standards as a reference point for developing national standards and practices.

Using AABB guidelines, the electronic crossmatch is possible only if the following conditions are met:

hotlink The patient's ABO group and Rh type has been done twice and entered in the computer (one group can consist of a record but one must be done on a current in-date specimen). * The computer must alert the technologist if there is a discrepancy between the two groups.

hotlink The donor ABO (and Rh types, if negative) have been confirmed and entered in the computer. The donor' unit identification number, component name, and ABO/Rh type must also be entered in the computer (manually or by scanning the bar code label on the unit).

hotlink* The computer system will alert the technologist to ABO & Rh discrepancies between information on the donor label and results of donor confirmatory testing.

hotlink The computer system will alert the technologist to ensure correct data entry and interpretation, e.g., prevent group O test results from being misinterpreted as group A.

hotlink *The computer system will alert the technologist to ABO and Rh discrepancies patient and donor groups. The program should be programed to prevent assigning ABO incompatible blood (e.g., group A red cells to a group O recipient) and to give an alert when assigning Rh-positive red cells to Rh-negative recipients.

*These three functions must be done electronically. The other AABB requirements can be met by standard operating procedures (SOPs).

Note that an electronic crossmatch is nothing more than using a computer to assign a unit of blood to a patient. The sole purpose of the electronic crossmatch is to confirm ABO compatibility between patient and donor. It cannot prevent hemolytic transfusion reactions caused by patient antibodies that are missed by the antibody screen; it cannot prevent hemolytic reactions due to patient misidentification errors.

Note: Most transfusion services do not yet use the electronic crossmatch because their information systems do not meet the AABB criteria.


Computer-assisted crossmatches must not be done for patients with:

hotlink a record of clinically significant antibodies (even if they are now undetectable)

hotlink currently detectable clinically significant antibodies

hotlink unresolved ABO discrepancies

Trends Electronic Crossmatch